Research focuses on impact cratering processes as revealed by laboratory impact experiments, the planetary surface record, and terrestrial ground truth. Laboratory research includes atmospheric effects on ejecta emplacement, impactor survival, secondary impact processes, antipodal shock effects, high-speed spectroscopy of impact vapor/plasma, impact angle effects (shock propagation, vaporization, target damage, and flow-field evolution), projectile fate after impacts, and crater-scaling relations. Of particular interest has been the origin of fluidized ejecta and blast winds around craters on Mars. Such basic research led to participation in numerous NASA planetary missions including Magellan, Deep Impact, Stardust-NExT, EPOXI, and LCROSS. Other basic research about the Moon includes: floor-fractured craters, beginning/end of volcanism, recent lunar activity (tectonism, impacts, and surface processes), lunar swirl generation, polar volatile evolution, assessment of the size of impactors, and origin of the nearside/farside dichotomy. The last study argued that the distribution of smooth lava plains on the lunar nearside originated as the result of a giant oblique impact (the South-Pole-Aitken Basin) on the far side. On Earth, his research has included the distribution of ejecta around Meteor Crater, discovery of 8 impact glass layers in Argentina, documentation of a witnessed crater-forming impact in Peru in 2007, and the widespread distribution of glasses generated by an airburst across the Atacama Desert (Chile) about 11,500 years ago.